Caking bomb assembly



'May 26, 1959 M. D. BARNES ETAL CAKING BOMB ASSEMBLY 2 Sheets-Sheet 1Original Filed Aug. 8, 1951 FIG.

FIG. 2

Marion D. Barnes James P. Leo

IN V EN TOR.

ATTORNEY y 1959 MD. BARNES ETAL 2,387,945

CAKING BOMB ASSEMBLY Original Filed Aug. s, 1951 2 Sheets-Sheet 2 FIG. 4

Marion 0. Barnes James P. Leo

INVENTOR.

&

United States Patent 2,887,945 CAKING BOMB ASSEMBLY Marion D. Barnes andJames P. Lea, El Dorado, Ark., asslgnors, by mesne assignments, toMonsanto Chemical Company, St. Louis, Mo., a corporation of DelawareOriginal application August 8, 1951, Serial No. 240,942, now Patent No.2,762,294, dated September 11, 1956. Divided and this applicationNovember 14, 1955, Serial No. 547,255

1 Claim. (Cl. 100-99) This invention relates to a caking bomb assembly,and more particularly to an apparatus for simultaneously prepallging aplurality of specimens in the form of compressed c es.

Considerable eifort has been made in the fertilizer industry to minimizethe tendency of fertilizers to cake. While much progress has been madealong this line, the caking problem still exists. For instance, ammoniumnitrate is manufactured in the form of pellets and the pellets coated inorder to reduce caking. In view of the foregoing, as a control measure,it is necessary to provide means for preparing a large number ofspecimens for making caking tests. Accordingly, the present inventionrelates to an apparatus for preparing such specimens.

Although not limited to such application, the invention will bedescribed with reference to apparatus particularly adapted forsimulating the conditions to which bagged fertilizer is subjected duringstorage in order to determine the caking properties thereof. For thispurpose, fertilizer is pressed into cakes under controlled conditions asto pressure, temperature, and humidity during a period of about oneweek. Tendency to cake then is measured as the pressure required tocrush the cakes, as in a Carver laboratory press.

This invention will be understood more readily from the followingdescription of apparatus forming various embodiments thereof.

Referring to the drawings generally:

Figure 1 is a side elevation, partly in section, of a caking bomb andassembly rack.

Figure 2 is a plan view on line 2-2 of Figure 1.

Figure 3 is a section view on line 33 of Figure 1 showing details of thecup in which the cakes are formed.

Figure 4 is a side elevation showing the modification of this inventionin which pressure is applied by means of a fluid system.

Figure 5 is a side elevation showing the modification of the embodimentillustrated in Figure 4, a fluid system being provided both for applyingpressure and maintaining the pressure constant.

Referring to the drawings in greater detail:

Numeral 1 represents a rack or frame adapted to accommodate any desirednumber of bombs 2. Each bomb unit comprises metallic double wall bellows3 to which is securely attached a head 4 held in the opening 5 of therack with cotter pins 6 and communicating with the bellows through atapped opening 7 into which a pressure gauge 8 is threaded. The bellowsis filled with a fluid such as an organic fluid (e.g. mineral oil,dibutyl phthalate), water, or air in order to transmit the pressure tothe gauge which is applied to the cake 9 by tightening the jack screw 10threaded into the base plate 11 of the rack.

The cake-forming cup 12 of the bomb comprises an outer pipe 13 into thebottom of which is threaded an ordinary barrel bung 14 having a rod 15attached in the well thereof more or less as a filler. Restingunattached on top of the bung is a metal plate 16 of substantially the2,887,945 Patented May 26, 19 59 same diameter as the inside diameter ofthe outer pipe 13.

A pipe 17 split in half longitudinal fits inside the outer pipe 13 andrests on the plate 16. The material, e.g. am monium nitrate pellets 18,to be pressed is placed in the cup 12 thus formed and a metal plate 19is laidon-top of the material. As indicated above, the desired pressureis applied to the ammonium nitrate by tightening the jack screws 10.

The entire assembly of bombs and the rack are placed in a cabinet (notshown) and the ammonium nitrate is subjected to controlled conditions asto pressure, temperature and humidity for about one week. Then theammonium nitrate cakes formed are removed from the bomb by loosening thejack screw 10, removing the cakeforming cup 12 from between the jackscrew and bellows, and removing each half of the split pipe 17. Tendencyof the ammonium nitrate to cake is then determined by measuring thepressure required to crush the cakes, e.g. in a Carver laboratory press.

The above described bomb works well but in order to increase thecapacity of a given size rack and at the same time reduce the cost ofthe bomb and to make other improvements, the following describedapparatus (Figures 4 and 5), comprising this invention, was devised.

Instead of the jack screws 10, a fluid system 27 can be used to applypressure in forming the cakes. Any suitable fluid, such as oil, water orair, is applicable. The fluid system shown comprises a main fluid supplyline 28, branch lines 29 leading to the bellows in each of the bombs,compression-type tubing Ts 30 and symbol 31 with valve stem 32, andflare type adapters 33. Only one pressure gauge 8 is needed for oneentire bomb assembly. The desired pressure on the cakes is obtained byintroducing fluid into the fluid system 27 through the valve stem 32. Ifair is used, an ordinary tire pump is suflicient for introducing thefluid.

In connection with the above described apparatus, it was found in mostcases that during about the first day of the cake-forming operation theammonium nitrate would settle, thereby causing a decrease in volume anda corresponding drop in pressure. In order to maintain a reasonablyconstant pressure, this made it necessary for the operator to check thebombs periodically and compensate for the pressure drop by tighteningthe jack screws 10 or adding fluid through the valve stem 32.

According to this invention a means of applying a substantially uniformpressure automatically is shown in Fig. 5. In this embodiment the mainfluid supply line 28 is attached to a fluid supply source (not shown),e.g. air, throughout the cake-forming operation. The constant pressurevalve 42 maintains the pressure constant.

'Ilhis application is a division of application Serial No. 240,942,filed August 8, 1951, now U.S. Patent 2,762,294.

What is claimed is:

Apparatus for simultaneously preparing a plurality of .test samples ofgranular material of the type which tends to coalesce in storagecomprising a rigid frame, said frame having a top member, a spacedbottom member and connecting side members, a series of pressureresponsive metallic bellows depending from said top member, pressureindicating means communicating with said bellows, a series of cylinderassemblies supported upon said bottom member in alignment each with oneof said depending bellows, said cylinder assemblies each being comprisedof an upstanding outer cylinder open at both ends, a bottom closuredetachably secured in the lower end of said outer cylinder, anunattached bottom disk of less diameter than said outer cylinder restingupon said bottom closure, a divided cylinder insert resting upon saidbottom disk and protruding above the free end of said outer cylinder, atop pressure disk of less diameter than said insert having slidingcontact with the inner walls thereof, means for applying pressure to thesamples of granular material disposed between said top pressure disksand said bottom disks of said cylinder assemblies, said top diskhavingcontact with the free ends of said bellows upon the application ofpressure to said samples, .and a constant pressure valve forcompensating for the drop'in pressure on said samples due to the gradualcoalescence thereof during prolonged exposure to temperin storage.

References Cited in the file of this patent UNITED STATES PATENTS

